1. Field of the Invention
The present invention relates to a toner cartridge for supplying toner in electronic copying machines, printers, and the like.
2. Description of the Related Art
Conventionally, a perfectly sealed container is used for a toner cartridge, in order to completely shut out moisture. This type of toner cartridge can prevent toner from cohering together within the cartridge by completely shutting out moisture. Since the container is hermetically sealed, there is a danger that it will burst when temperature and pressure vary during transportation or the like.
In the case of the toner cartridge of the open type, it is impossible to perfectly protect the contained toner from moisture. Accordingly, this type of toner cartridge suffers from toner cohesion and deterioration of toner quality.
In order to remove the above defects, Unexamined Japanese Utility Model Publication No. Hei. 3-71362 discloses a toner cartridge 101 as shown in FIGS. 1(a) and 1(b). A cylindrical cartridge body 102 is provided with the toner cartridge 101, in which one end opening portion 102a is sealed. A toner discharge portion 103 having a toner discharge hole 104 is provided on the side surface of the cartridge body 102. The toner discharge hole is sealed by a sealing member 105. A rolling portion 106 for rolling the sealing member 105 is provided with the cartridge body 102. A cover 107 having an air hole 108 is mounted on the other end opening portion 102b of the cartridge body 102. An air filter 109 for covering the air hole 108 is mounted on the cover 107. On the outside of the cover 107, a deflated bag member 110 is provided. The cover portion as shown in FIG. 1(b) is inserted into the opening portion 102b from the direction of an arrow indicated in the right side of FIG. 1(a). When an inner pressure of the cartridge body 102 is increased, air flows into the bag member 110 to adjust the inner pressure, whereby moisture is shut out.
In addition, Unexamined Japanese Patent Publication No. Hei. 4-359274, discloses another toner cartridge, shaped like a box, in which a sheet member at the temperature of 4.degree. C. to 300.degree. C. in the coefficient of air permeability is coated with adhesive, and a toner discharge port of the main body of the container is heat sealed with the sheet member.
In the case of the former toner cartridge disclosed in Unexamined Japanese Utility Model Publication No. Hei. 3-71362, it is provided with the bag member, and hence is of the closed type. Accordingly, it is capable of shutting out moisture. However, when the inner pressure is high, the bag member is inflated so as to occupy an excessive space in an apparatus such as a printer, copy machine or the like. In addition, many parts are used to mount the bag member, thereby impairing the manufacturing efficiency. Further, since the inner pressure is high, the bag member remains inflated. This inflated state makes it difficult to mount the bag member on the apparatus.
In the case of the latter toner cartridge disclosed in Unexamined Japanese Patent Publication No. Hei. 4-359274, the air permeable sheet member is provided on the toner discharge port so that the air permeating area is large. Accordingly, when it is not used for a long time, for example during storage, a blocking phenomenon where toner coheres together takes place. When the toner cartridge is set to the apparatus and toner is supplied, scattering of toner takes place.